1. Field of the Invention
This invention relates to removable, movable closures, more specifically to a pivot shoe connected by rotation transmission means to a sliding window sash, the shoe being located in the window jamb track for sliding one end of the sash along the track and for preventing sliding by pressing against the track when another end of the sash is rotated away from the track on the pivot shoe.
The shoe provides the option of permitting removal of the sash from the jamb or preventing its removal from the jamb, simultaneously with it preventing sliding of the shoe along the track.
The shoe is necessarily locked against movement in the track when the sash is removed because without the weight of the removed window expressed upon the shoe, the counterbalance mechanism applied to the shoe would case it to fly upwards in the track.
2. Description of the Prior Art.
Locking pivot shoes which permit removal of the sash from the jamb are disclosed in the prior art by many different designs. U.S. Pat. No. 3,611,636, patented Oct. 12, 1971 by D. M. Trout, discloses a shoe having a sharp, cylindrical, rotary, radial cam operated pawl which engages the track for locking the shoe against movement along the track when the window sash is rotated away from the track.
A pivot upon which the window rotates includes a key which removably seats in a notch with radial opening in the rotary locking cam. The cam rotates in a cylindrical bore which comprises a part of the shoe.
When the sash is vertical, that is, aligned with the track, the notch is oriented horizontally so that the radial opening of the notch is blocked by the inward face of the bore, thereby preventing removal of the key from the shoe.
When the sash is rotated to the horizontal, the cam is rotated 90 degrees by the key so that the opening of the notch is vertical and in alignment with a vertical, axially oriented slot in the bore, as the pawl is forced into locking engagement with the track.
Alignment of the notch with the vertical slot enables the operator to lift the pivot and key out of the notch, up the slot, and out of the shoe. The operator tilts the sash by raising one side and removes it by pulling it out of the jamb while the sash is in an oblique or diagonal position relative to the tracks.
The sash is reinstalled by reversing the above procedure.
U.S. Pat. No. 4,364,199, patented by Johnson et al., Dec. 21, 1982 discloses a shoe which rides in a track having four parallel vertical ribs. The show locates by included slots in the shoe, on the two inner ribs, and as a whole it locates within the two outer ribs.
A pivot upon which the sash rotates includes a key which removably seats in a notch with radial opening, within a rotary cam. The cam rotates in a cylindrical bore with vertically oriented axial slot, which comprises a part of the shoe. The cylindrical bore tangentially intersects the slots.
When the sash is vertical, the notch is oriented horizontally so that the radial opening is blocked by the bore.
When the sash is rotated to the horizontal, the cam is rotated 90 degrees by the key so that it bears radially directly against the two inner ribs of the track, forcing them radially against the portion of the shoe which lies between the inner and outer ribs of the track. Simultaneously with this locking action in the track, the radial opening in the cam lines up with a vertical opening in the bore of the shoe. This permits removal of the sash by lifting the pivot and key out of the notch. Adjacent to the sash, the pivot includes an annular cam face which presses against the track to draw the pivot key back from the base of the track to aid in removal of the sash.
If it is desired to prevent removal of the sash, a plug with depending feet having outwardly extending fingers is provided for blocking the vertical opening in the shoe. It is installed by engaging the fingers in horizontal grooves provided in the walls of the vertical opening in the shoe.
In U.S. Pat. No. 4,718,194, patented Jan. 12, 1988, FitzGibbon et al, discloses a slider body diagonally split at one end. The split inludes a portion shaped to conform to a sash pivot shaft actuated barrel cam when the sash is oriented with the track for sliding. One of the legs established by the split in the slider body includes a pin. The pin is forced radially against an inner face of a side wall of the track when the legs are spread by the radial cam as it rotates with the tilting window.
The cam includes a radial opening, and the slider body includes a vertical opening, whereby the pivot shaft can be lifted vertically from the cam and slider body via the aligned openings when the sash is rotated away from the window frame.
In U.S. Pat. No. 4,922,657, patented May 8, 1990 by R. Foss, the track is bedded in a resilient material so that the sash can be removed by forcing it against one track, therby drawing the pivot pin axially out of the pivot shoe.
The track has three parallel vertical ribs, a first and a third, one on each side of the shoe, and the second one received in a vertical slit in the shoe. A pinch roller rests in an oblong track that is tilted form the vertical so that the roller tends to fall against the second rib, pinching it between the roller and the opposite side of the slit.
The pivot pin, when inserted in the shoe, prevent the roller from falling against the seocnd rib so that the shoe can move freely in the track. When the pin is withdrawn from the shoe, the roller prevents the shoe from sliding in the track.